Back-to-school is just a few short weeks away. While it might be an exciting time for kids, for parents, the cost of new clothes and school supplies can be dreadful. But you can save big with an easy trick called “deal stacking,” according to financial advice writer Jamie Cattanach.

“The idea is, basically ... going above and beyond and seeing how you can layer multiple deals on top of each other to get the best possible price on that item,” Cattanach tells NBC News BETTER. Here’s how you can stack multiple deals on your kid’s back-to-school essentials.

Find a store near you with the best deals

The cost of school supplies and clothes can really add up, especially if you’re shopping somewhere expensive. Skip the high-end stores and find one with the best deals instead. Once you’ve found it, look for sales and coupons on the items your little one needs.“Obviously, you wait for [a sale] and then also once you’re there, you shop the sales rack, so it’s not just the overall sales, it’s something that’s even more deeply on clearance,” explains Cattanach.

Make your purchases with a used gift card

Once you’ve found a store with the best deals, you can save even more by purchasing a used gift card online for that store, advises Cattanach. You can find great deals for used gift cards online on Raise, eBay, Craigslist and from individuals selling them on Facebook, she said.

For example, someone who received a $50 gift card for Walmart may sell the card to you for $40 on one of these sites.“Which means you just spent $40 to buy $50 worth of buying power at the store that you’re going to shop at,” said Cattanach.

Get rewarded for money you spend

To save even more money on your purchases, Cattanach recommends buying your discounted gift card with a cash-back rewards credit card. Even if the reward is just one percent of every dollar spent, you’re still saving, she explains.

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You’re earning back a certain percentage of every dollar you spend on that credit card,” she says. “So it’s basically just trying to find as many ways as possible to shave off — even if they’re small increments — as much of the price as you can.”

But she warns that for this to work, you need to pay off your card in full each month, or the interest you pay on carrying the balance will cancel out your earnings.

“You definitely want to make sure you’re not carrying a revolving balance on a credit card — ever,” says Cattanach.

Use online portals

Online portals like Ebates, which offers cash back when you purchase items from over 2,000 stores, can help you save even more money, Cattanach says. And if you purchase your kid’s school supplies with your used gift card (which you bought with that cash-back rewards credit card), the savings really pile up.

How it all stacks up

Let’s say you have $40 to spend on school supplies:

You find a store with the best prices for buying supplies.

You purchase a $50 gift card for that store, but it costs you just $40 because you bought it used.

In addition, you purchased your used gift card with a cash-back rewards credit card that offers one percent cash rewards for every dollar you spend.

You find a coupon for 25 percent off at your store.

How much do you save?

Discounted gift card: $10

Cash-back rewards: $0.40

Coupon: $10

Total savings: $20.40

Going the extra mile doesn’t just save money, it feels good

“There is a certain level of feeling, like it’s achievement unlocked,” says Cattanach. “Not [like] cheating the system so much, but definitely getting a better deal than would be possible if you didn’t go the extra mile and that does feel good.” How to deal stack:

Find a store with the best deals: Don’t shop at a high-end store. Instead, find a store with the best bargains.

Make your purchases with a used gift card: Shop online for used gift cards, which you can purchase for less than their value.

Get rewarded for money you spend: Buy your discounted gift card with a cash-back rewards credit card. Even if the reward is just one percent of every dollar spent, you’ll still save.

Shop with online portals: Consider shopping on an online portal like Ebates, which offers cash back when you purchase items from over 2,000 stores.